Summary form only given. The ionized PVD technique is used for barrier and seed layer metallization in advanced IC wafers. It provides good sidewall and bottom coverage in via and trench structures, and it is promising to extend performance up to sub-mum technology. To control deposition and etching rates at substrate during liner and seed deposition process and provide optimal conditions for good coverage of the high aspect features an RF bias power is applied at substrate electrode. However, at increased pressures some of the sputtered material will be scattered back. Generally, it is accepted that during etching processes, some of the removed (etched) material returns to the surface of the substrate in the form of re-deposition. The ionized PVD is realized in pressure range from several mtorr to 90 mtorr. At very low pressures (<5 mT), this re-deposited amount has negligible impact on process performance and can be discounted. At pressures greater than 5 mT, the amount of re-deposition to the substrate can be significant and affect actual feature coverage. When substrate feature sizes are very small, the impact of re-deposition to the substrate can be obscure and feature etching performance unrealized. The re-deposited material to the substrate can have ionization properties very different from the original deposited material. To investigate the effect we developed a technique to isolate the redeposition from the actual etch rate performance to understand the impact of re-deposition on 60-200 nm features. The process pressure and table bias power were examined in wide range to investigate a re-deposition impact on etch uniformity. We develop a model to simulate this effect, and evaluated the re-deposition effect quantitatively at given process conditions

Fluvastatin is a potent synthetic competitive inhibitor of beta-hydroxy-beta-methyl-glutaryl-coenzyme A (HMG-CoA) reductase, the rate-limiting enzyme in the biosynthetic pathway for hepatic cholesterol synthesis. The therapeutic indication is reduction of elevated total and low-density lipoprotein cholesterol levels. Results from four toxicity studies in beagle dogs and one study in rhesus monkeys following oral administration of fluvastatin are reported. In two 26-week dog studies, doses were 0, 1, 8, or 48 mg/kg/day (reduced to 36 mg/kg/day in Week 7) and 0, 6, 24, or 36 mg/kg/day (reduced to 30 mg/kg/day in Week 2). In a 2-year dog study, doses were 0, 1, 8, or 16 mg/kg/day. Dose levels in the 26-week monkey study were 0, 0.6, 12, and 48 mg/kg/day (raised to 84 mg/kg/day in Week 17 and to 108 mg/kg/day in Week 22). In these studies, evaluations included clinical and physical examinations, body weight and food consumption, electrocardiography, ophthalmoscopy, hematology and clinical chemistries, urinalysis, blood drug concentration, and macroscopic and microscopic examinations of observed lesions and representative tissues. In the 26- and 52-week dog studies and the monkey study, lenticular biochemistry, the HMG-CoA reductase activity of liver microsomes, and serum lipid concentrations were investigated. The fourth dog study was a single-dose toxicokinetic study in which 48 mg/kg [3H]-fluvastatin was monitored for up to 2 weeks. Sampling was limited to ocular tissues for enzyme analysis. Doses of > or = 24 mg/kg/day were lethal in dogs. At lethal doses, ataxia, convulsions, fecal blood, multifocal congestion and hemorrhage, isolated foci of malacia in the medulla oblongata, and liver necrosis were observed. Reduced weight gain, emesis, cataracts, elevated liver enzymes, reduced cholesterol, and gallbladder inflammation with mucosal hyperplasia occurred at > or = 8 mg/kg/day. In contrast to other HMG-CoA reductase inhibitors, fluvastatin did not cause significant central nervous system hemorrhage or testicular changes in dogs. Monkeys tolerated exposure to fluvastatin well with only mild gallbladder changes observed. Reduced serum cholesterol and slight hyperplasia of the gallbladder mucosa occurred in the 12 and 48/84/108 mg/kg/day groups.

The tolerability and potential target organ toxicity of rhIL-6 administered subcutaneously (s.c.) with rhGM-CSF or rhG-CSF were investigated in healthy nonhuman primates. Fifteen Rhesus monkeys were randomized to receive one of the following five regimens: rhIL-6, rhGM-CSF, rhG-CSF, rhIL-6 and rhGM-CSF, or rhIL-6 and rhG-CSF. Each cytokine was administered s.c. once daily at 20 μg/kg/day for 30–31 days. Marked increases in blood leukocyte counts (predominantly neutrophils) were observed in the rhGM-CSF and rhG-CSF treatment groups, but only a mild trend toward increased WBCs was observed with rhIL-6 alone. Platelet counts increased 1.7- to 2.2-fold in the rhIL-6 and rhGM-CSF groups. All regimens were well tolerated. RhIL-6, alone or in combination with either CSF, had no significant toxic effects at the dosages tested. Minimal to moderate bone marrow hyperplasia was observed in all except rhIL-6-treated animals, which correlated well with peripheral blood increases in WBCs. RhIL-6-treated animals demonstrated increased fibrinogen concentrations and erythrocyte sedimentation rates, decreased serum albumin/globulin ratios, and increased serum α-2-macroglobulin concentrations. Increased synthesis of acute-phase proteins was not observed in the other groups. Combining rhIL-6 with rhGM-CSF or rhG-CSF may reduce the rhIL-6-mediated acute-phase response while maintaining the desirable hematopoietic effects of the stimulating factors.

The HMG-CoA reductase inhibitors are a new and novel class of cholesterol-lowering agents which are widely used worldwide. Fluvastatin is the first entirely synthetic compound in this class and is structurally distinct from fungal metabolite derivatives which are already marketed. As the liver is the site of some toxic effects for these compounds, it was not entirely unexpected that liver cancer was found in rats and/or mice with the first three marketed compounds, lovastatin, pravastatin, and simvastatin. Four lifetime carcinogenicity studies (two rat and two mouse) did not give any evidence that fluvastatin induced liver tumors in rodents. Fluvastatin induced thyroid neoplasms in rats and forestomach papillomas in rodents, as other compounds in this pharmacologic class have also done. The genotoxic potential of fluvastatin has been assessed in vitro using Salmonella typhimurium, Escherichia coli (gene mutations), V79 Chinese hamster cells (HGPRT gene mutations, chromosomal aberrations), rat hepatocyte primary cultures (DNA repair), and BALB/3T3 cells (malignant transformations). Fluvastatin was also tested in vivo for clastogenicity using the mouse bone marrow micronucleus test and by performing a cytogenetic analysis in the rat bone marrow after acute and subacute treatment. In all seven assays fluvastatin was found to be free of any genotoxic potential.

Numerous amphiphilic cationic drugs cause generalized phospholipidosis in animals; one of these drugs is the Sandoz compound 200-125, a psychotropic agent. During a 6-month toxicity study in Charles River CD rats, a dramatic increase in foamy macrophages was seen in the lungs. A follow-up experiment was done to study the pathologic basis of these changes including a reversibility phase. Generalized phospholipidosis was induced after 4 weeks of 500 mg/kg/day of 200-125 by gavage. Characteristic pulmonary lesions consisted of extensive accumulations of large pale foamy macrophages as well as granular eosinophilic extracellular material. Lipid analyses of lungs showed marked increases in phospholipids (144%) and cholesterol esters (110%) in rats treated with 200-125. Drug metabolism studies employing 14C-labeled 200-125 showed an affinity for the drug to concentrate in the lungs and lymphoreticular system (spleen, lymph nodes) as well as in the adrenals, liver, and kidney. Reversibility of the phospholipidosis was nearly complete 4 weeks after drug withdrawal. The tissue changes were characterized by transmission and scanning electron microscopy. The potential pulmonary toxicity in humans with the amphiphiles is discussed.

It was our goal to evaluate the reliability and reproducibility of semi-automated morphometric techniques in the analysis of structural changes observed during drug safety assessment. Studies are presented to correlate the ultrastructural, morphometric and biochemical effects that the two hypolipidemic agents, clofibrate and probucol, produce in rats.Charles River CD Sprague-Dawley derived male rats (200-225 g body wt.) were used for the three studies performed. In studies I and II, clofibrate was administered as a dietary admixture to approximate a dosage of 300 mg/kg/day for six days. In study III, clofibrate and probucol were given as dietary admixtures to approximate dosages of 300 and 250 mg/kg/day respectively for fourteen days. Processing of hepatic specimens for electron microscopy included fixation in 1.3% sym-collidine buffered osmium tetroxide, ethanol dehydration and Epon embedment. Thin sections (600Å) were stained with uranyl acetate and lead citrate. Survey and photography was performed in the manner according to Weibel. Final prints (14,400x) were analyzed with a Zeiss MOP for morphometric quantitation.